The present invention pertains to simulated battlefield position location and more particularly to passive position location for determining the effects of simulated munitions deployment on a target.
Position detectors may be used to find the location of individuals or vehicles with respect to simulated munitions to determine whether injury or damage was inflicted on the individuals or vehicles. A battlefield for a war game is established. Boundaries of this battlefield are marked by actuators. These actuators emit coded transmissions which cover the area of the battlefield. These location detectors may be active or passive. Active location detectors interact with the actuators to both receive messages from the actuators and transmit messages to the actuators. Passive location detectors receive transmissions from the actuators and determine their position relative to a predetermined impact point of the munition.
Active location devices contain transmitters and receivers. Passive location devices include receivers only By eliminating the transmitter portion of a position locator, passive location detectors may be made to be less expensive, more reliable and more operable in a hostile environment.
Doerfel et al. U.S. Pat. No. 4,682,953, issued on July 28, 1987 and Doerfel et al. U.S. Pat. No. 4,744,761, issued on May 17, 1988 teach and describe one such passive location detection device. This passive location device uses a time-windowing technique which generates a polygon-shaped area in which the target is probably located. The number of sides of this polygon is related to the number of actuators used. For example, three actuators generate a six-sided polygon. When the target PDD is located along a border of the polygon area encompassed by the actuators, the polygon produced is substantially elongated and distorted. Such distortion of the area in which the target Passive Detection Device (PDD) is located results in a possible indication of harm or damage when none was truly inflicted or a possible indication of no damage when damage was actually inflicted. Because the target PDD is located only within a bounded area and because of the distortion when a PDD is near the boundary of the actuator area, the passive location device described in the references can produce many false readings.
As a result, it is an object of the present invention to provide a passive location detector which determines the 15 actual coordinate position (rather than position within a window) of a target PDD with minimal error.